The geeglm function fits generalized estimating equations using the 'geese.fit' function
of the 'geepack' package for doing the actual computations. geeglm has a syntax similar to
glm and returns an object similar to a glm object.
An important feature of geeglm,
is that an anova method exists for these models.
No action is taken. Indeed geeglm only works on
complete data.
start
See corresponding documentation to glm
etastart
See corresponding documentation to glm
mustart
See corresponding documentation to glm
offset
See corresponding documentation to glm
control
See corresponding documentation to glm
method
See corresponding documentation to glm
x
See corresponding documentation to glm
y
See corresponding documentation to glm
contrasts
See corresponding documentation to glm
id
a vector which identifies the clusters. The length of ‘id’
should be the same as the number of observations. Data are
assumed to be sorted so that observations on a cluster are
contiguous rows for all entities in the formula.
waves
Wariable specifying the ordering of repeated mesurements on the same unit.
Also used in connection with missing values. See examples below.
zcor
Used for entering a user defined working correlation structure.
corstr
a character string specifying the correlation structure. The
following are permitted: '"independence"', '"exchangeable"',
'"ar1"', '"unstructured"' and '"userdefined"'
scale.fix
a logical variable; if true, the scale parameter is fixed at
the value of 'scale.value'.
scale.value
numeric variable giving the value to which the scale
parameter should be fixed; used only if 'scale.fix == TRUE'.
std.err
Type of standard error to be calculated. Defualt
'san.se' is the usual robust estimate. Other options are 'jack':
if approximate jackknife variance estimate
should be computed.
'j1s': if 1-step jackknife variance estimate
should be computed.
'fij': logical indicating if fully iterated jackknife variance
estimate should be computed.
...
further arguments passed to or from other methods.
Details
In the case of corstr="fixed" one must provide the zcor vector
if the clusters have unequal sizes.
Clusters with size one must not be represented in zcor.
Value
An object of type 'geeglm'
Warning
Use "unstructured" correlation structure only with great care. (It may
cause R to crash).
Note
See the documentation for the 'geese' function
for additional information. geeglm only works for complete data. Thus
if there are NA's in data you can specify data=na.omit(mydata).
Author(s)
S<c3><b8>ren H<c3><b8>jsgaard, sorenh@agrsci.dk
References
Liang, K.Y. and Zeger, S.L. (1986) Longitudinal data analysis
using generalized linear models. Biometrika, *73* 13-22.
Prentice, R.L. and Zhao, L.P. (1991). Estimating equations for
parameters in means and covariances of multivariate discrete and
continuous responses. Biometrics, *47* 825-839.